This invention relates to a closure for a bottle particularly a bottle with liquid contents which may be under a positive pressure. The closure includes a tilting nozzle through which the contents of the bottle are discharged.
Previously such closures have included a cap made from a plastics material with its side wall carrying an internal annular bead adjacent its open end for engagement with the neck of the bottle and its end wall including a tubular nozzle, the closure has also included a closure member arranged to seal against the open end of the bottle neck, the arrangement being such that the closure member can be partially lifted off the open end of the neck by a force applied laterally to the nozzle to tilt it, to discharge the contents of the bottle.
A known tilting nozzle closure of this kind is described in West German Offenlegungsschrift No. 2530232 and in the closure described in this specification the closure member is formed by the closed bottom end of the tilting nozzle. The nozzle is sealed through a central opening in the end wall of the cap and the closed bottom end of the nozzle includes an outer flange which engages the underside of the thickened rim portion of the end wall of the cap adjacent its side wall. When the closure is fitted on to the neck of a bottle the end wall of the cap engages the flange around the closed bottom of the nozzle and urges it against the open end of the bottle either directly or via an annular seal insert formed by soft, resilient material. The nozzle communicates with an annular chamber formed between the side wall of the cap and the upper end of the neck of the bottle by means of at least one radial duct through the side wall of the nozzle.
This closure suffers from various disadvantages. It is difficult to obtain a reliable seal between the closure member and the neck of the bottle when the closure does not include a separate sealing insert and this does not permit the closure to seal the bottle reliably when the contents of the bottle are under a positive pressure. Further, when the closure member includes a sealing insert a greater degree of tilting movement of the closure member is required before the contents of the bottle can be discharged.
Furthermore, the axial stress applied to the closure member to urge it against the open end of the bottle neck has to be provided by the side wall of the cap and, when the closure member is tilted to discharge the contents this axial stress in the side wall of the cap is increased. Firstly, this makes it more difficult to ensure a tight and positive sealing engagement between the annular bead on the internal face of the side wall of the cap and the outer annular bead on the bottle neck and, secondly, increases the risk that the cap will become disengaged from the bottle neck when the axial stress in the side wall is increased by tilting the nozzle. There is also a risk that, as a result of the transverse force applied to the nozzle to tilt it, the closure member will be displaced radially with respect to the open end of the bottle and, thereafter, not form an effective seal. Finally, it is possible that the duct through the side wall of the nozzle, particularly when this is opposite the point at which the transverse force is applied, will be constricted or closed when the nozzle is tilted.
Another closure is shown in the specification of West German Gebrauchsmuster No. 7036290 which is specifically arranged to be used with a bottle having contents under positive pressure. In the closure described in this specification the cap includes a resilient annular connection between the nozzle and the rim of the end wall together with a separate closure member and a sealing washer which is clamped between the open end of the neck of the bottle and the end wall of the cap. The separate closure member is located in the inside of the bottle neck and includes a spigot extending through the washer and into the inside of the nozzle. The closure member is urged towards the end wall of the bottle where it engages against the lower face of the sealing washer to form a seal by the pressure of the contents in the bottle.
The construction of this three part closure is complex and it is, therefore, difficult to produce and install. Moreover, the seal of the closure is only ensured whilst the internal positive pressure of the contents of the bottle is sufficient to thrust the closure member against the sealing washer.